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dario84 avatar image
dario84 asked

Difference between outputs watts from battery and AC Loads

Hello everyone,

I have a problem with my easy solar 2 gx device (24V system), on a standalone solar system (no connection to grid)

During the night, AC loads are 27 watts (only a router and a camera), but battery discharging is around 100W.

Self consumption of easy solar should be 13W, and the integrated mppt smart solar should be OFF.

I have 4 batteries Opzs of 150Ah, connected in series and parallel.

Cables are very short (less than 2m) and are of the recommended section (50mm2).

More than so, I have a battery shunt, but I don’t thing it have a big self consumption.

On AC Loads I have lights and sockets, but during the night are not in use.

Could someone help me to understand where could be (and maybe how to find/measure) the lost of energy?

Thank you in advance!

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Multiplus-IIEasySolar All-in-One
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5 Answers
janieronen avatar image
janieronen answered ·

Unfortunately efficiency curve is not close maximum mentioned at small loads. If you easysolar2 is 24/3000 model it states 13W consumption on zero load. I would say DC-AC conversion efficiency at low power is apparently reason for your consumption. There is some additional losses as load has other charasterics than pure resistive load.


There is example measured efficiency curve from larger inverter but they have very similar characteristics. (copied from other thread)screenshot-2023-06-15-at-162242.png



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janieronen avatar image janieronen commented ·
About finding consumption details you can share AC and DC voltages/powers/amps during night via VRM advanced page. That's easy tool to analyse energy consumption and anomalies :)
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derrick thomas avatar image
derrick thomas answered ·

Have you done zero current calibration on the smart shunt? Beyond that, as others have stated, efficiency is going to vary slightly according to load.

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nickdb avatar image
nickdb answered ·

The units are not particularly accurate measuring for small loads so don't stress about it. Use higher constant loads for testing, it will be more reflective.

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seb71 avatar image
seb71 answered ·

To see what's actually the self consumption of your system, test with all loads disconnected.

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dario84 avatar image
dario84 answered ·

Thank you very much for your answers!

In advanced page all seems to be ok.

Tomorrow I will go to my cabin in mountains and I will do the calibration of the shunt (not done at the moment) and I will test the system with a stronger power, for example a vacuum cleaner.

I'm calmer anyway because it doesn't seem like there are any problems, and the energy consumption graph has clarified many doubts for me. pity that in the product details this detail is not specified.

due to the yield curve, maybe if I connect a freezer to the system I can have almost the actual battery consumption with same loss of watts (a freezer is about 50W of consumption) it would be nice! I just have to test that….

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